Hydraulic pump size for D2 5J with 2S dozer

If you go up in pressure, you could reduce the cylinder size down to modern conventional sizes. By holding yourself to the 1000psi limit, you'll need to increase Ram Cylinder size in my Opinion.

I'm going from memory here as I can't find my notes but I seem to recall the actual blade rate, going through what ever linkage is 1 to 1.5 ft/min. The #44 pump with wide cartridge is 37 gpm. (not recommended for D2). The narrow cartridge in a #44 D4 is 27 gpm., 25 gpm on the D2. Depends on the linkage arrangement as to what you will get for blade speed.
The #41 units on the D2 run about 14-15 gpm and were applied to tool bar dozers. No linkage involved, just the cylinder attachment angle to work with.
Any arrangement would be affected by changing cylinder size.

Good info, thank you.

I should have mentioned I was planning to use the original Cat cylinders for the 2S setup, just because I have them. That is what would limit me to the 1000 or 1200(?) psi value.

I had not considered changing the cylinders to modern versions. If so I doubt I can find ones that have the same eye size/length. Does anyone have experience with this upgrade though? It would be nice to have all new components. Smaller pump, hose size, tank size are all advantages.

Well I should have researched a bit on cylinders. They look to be fairly inexpensive, and I can probably refit the ends with compatible eyes, weld on.

Any other advice would be appreciated.

For whatever it's worth, I put a 16 gpm @1750 rpm rated pump on my 5J D2. I use two 3" x 16" cylinders direct connected to the C frame, and I get a travel on the cutting edge from about 10" below ground level to about 24" above. I am very satisfied with the speed, but you might want it faster.

When we built it about 1969, people at the shop marveled at 16 gpm! Back then the aftermarket equipment felt proud to have 8 or 10 gpm. I had found it too slow on an old JD, so doubled the pump output.

Hope this helps. Can you believe it? I've been running that same D2 5J 3691 for 47 years!

Hi Dan,
With the 44 pump I got from you then rebuilt, I'm satisfied with the speed.
Seems to work when you want it to